class listen:
    def __init__(self):
        print('hi listen')

    # 服务启动之前
    def before_server_start(app, loop):
        print("服务启动之前")

    # 服务启动之后
    def after_server_start(app, loop):
        print("服务启动之后")

    # 服务停止之前
    def before_server_stop(app, loop):
        print("服务停止之前")

    # 服务停止之后
    def after_server_stop(app, loop):
        print("服务停止之后")